Habitat Resources: Attracting Beneficial Bugs

National Wildlife
August/September 2000
By Michael Tennesen

When It Comes to Pestering Pests, Some Bugs Bug Other Bugs Best
Jake Blehm raises killers for a living. The killers are half-inch-long insects known as green lacewings. In the larval stage, lacewings must be kept in separate cardboard compartments or they'll eat each other.

To keep them mean and healthy, Blehm feeds them beef liver, chicken and other ingredients that he mixes in a blender.

"Lacewings love it," he says. "We call it our meat smoothie."

What makes these little cannibals worth raising is the way they devour aphids, mites, whiteflies, mealybugs, caterpillars and many other plant pests. To protect their crops from these pests, commercial farmers and home gardeners pay Blehm $15 for a carton of 5,000 lacewings. Blehm, president of Buena Biosystems, raises 250 million lacewings each year in his Santa Paula, California, insectary.

Blehm's insectary--a place for growing beneficial bugs--currently grosses more than one million dollars a year from the sale of lacewings and other pest-eaters. And demand for products from his center--one of several in the country--is growing at about 20 to 25 percent a year. Though worldwide revenue for insectaries is only a fraction of the income for the pesticide industry (less than $100 million a year vs. $9 billion a year), conservationists cheer the surging interest in beneficial insects as an alternative to the use of chemicals.

Beneficial creatures come in a wide variety: lacewings, ladybugs, predatory mites, tiny wasps and nematodes, among others. They eliminate pest insects in one of two main ways: They either parasitize them or prey on them directly. To demonstrate an example of the former, Blehm leads a visitor into a refrigerated room filled with large cartons of fly mummies. These are fly pupae, hard cocoons in which maggots metamorphose before emerging as flies. A closer look reveals tiny wasps stinging the mummies and depositing their eggs inside. These beneficial wasps eat dozens of species of flies that are known to bite humans and animals. So ranchers and farmers buy wasp-laden fly mummies from Blehm, which they then spread around their barns. The beneficial wasps feed on the fly pupae and emerge from the mummies, "Sort of like little aliens," says Blehm.

Blehm's insectary is just one of eight such facilities in Ventura County, making this part of California the mecca for beneficial bug businesses in the United States. Among the other businesses in the area is Novartis BCM. Novartis' most popular product is Persimilis, a predatory mite used by strawberry and ornamental plant growers. This tiny creature can eat as many as seven adult spider mites or 20 eggs per day. Spider mites feed on the leaves of strawberries and ornamentals.

Persimilis became popular among California strawberry growers in 1987, when Plictran, a pesticide for spider mites, was suddenly withdrawn from the market because it was considered dangerous to human health. "There was a valuable crop just sitting out there that needed to be protected," says Dan Cahn, president of Novartis BCM. "And beneficials were the only option."

Cahn is a proponent of integrated pest management--mixing beneficial insects with the careful use of newer pesticides that aren't as harmful to nontarget species. According to Cahn, one of the benefits of such a system is that pests don't develop resistance to chemicals as rapidly. Then if the farmer is forced to spray, the spray is more effective.

Other beneficial bug businesspeople in California take a dimmer view of chemical use. For example, Dorothy Neva, the founder of the Ladybug Company in Berry Creek, doesn't believe in pesticides at all. In fact, she blames pesticide use in California's Central Valley for the decline of ladybird beetles, which she and her daughter Julie catch wild in the foothills of the nearby Sierra Nevada Mountains.

The beetles, or ladybugs as they are commonly known, are famous for their voracious appetite for aphids: One adult ladybug can eat 100 aphids in a day. As a result, they are the best-sellers among beneficial bugs in the country. Neva gets her ladybugs from secret beds of leaf litter in the mountains near her home. (The majority of the ladybugs sold in the United States are wild caught.) The Ladybug Company is one of the largest distributors of ladybugs in the country, selling about 400 million of the beneficial beetles each year.

Neva, 72, practices what she preaches. In her own garden, she uses all of her company's products (which include green lacewings, trichograma wasps and praying mantises as well as ladybugs) to handle insect pests. And she is the envy of the neighborhood: "My neighbors all talk about how good my garden looks," says Neva.

To avoid pesticide use and get the neighbors talking about your garden, you need to watch your plants, keep track of the insect populations and learn to anticipate problems. "The trouble with most home gardeners is they do nothing until they start noticing the pest. But by then it may already be a major outbreak, and it's too late for beneficial insects," says Carol Glenister, president of the Association of Natural Bio-control Producers and owner of IPM Laboratories in Locke, New York.

One of the best ways to avoid pest outbreaks is to create your own insectary. Neva recommends growing a variety of flowering plants including sweet alyssum, dill, coriander and marigolds. The nectar of these flowers attracts traveling beneficial insects and gives them a reason to stay. Fill a dish or birdbath with water and you'll give beneficials a place to sit and slurp. Leave one corner of your garden wild and you'll help ensure insect diversity.

If it's not possible to create your own insectary, or you need to supplement your roster of beneficial insects, you'll need to do some research. A good place to start is the University of Vermont Extension Service's Web page on biological pest control: http://ctr.uvm.edu/ctr/pubs/apc817.htm. This site provides a helpful overview of beneficial insects, a list of commercial insectaries and a bibliography of key reference books on the topic.

Once you've received your shipment of beneficial insects, handle them carefully. Ladybugs can be stored in the refrigerator for as long as two months; lacewings can't be stored at all. Exposed mailboxes and closed cars on hot days can be fatal to beneficials. They may be killers, but they still need to be treated with kindness.